Anomalous conductances in an ultracold quantum wire

Abstract

We analyze the recently measured anomalous transport properties of an ultracold gas through a ballistic constriction [S. Krinner et al., PNAS 201601812 (2016)]. The quantized conductance observed at weak interactions increases several-fold as the gas is made strongly interacting, which cannot be explained by the Landauer theory of single-channel transport. We show that this phenomenon is due to the multichannel Andreev reflections at the edges of the constriction, where the interaction and confinement result in a superconducting state. Andreev processes convert atoms of otherwise reflecting channels into the condensate propagating through the constriction, leading to a significant excess conductance. Furthermore, we find the spin conductance being suppressed by superconductivity; the agreement with experiment provides an additional support for our model.

5 pages, 4 figures. Supplementary Material available as an ancillary file

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Cited by in corpus (3)

• Two-terminal transport measurements with cold atoms
• Thermopower and thermal conductance of a superconducting quantum point contact
• Anomalous Conductance of a strongly interacting Fermi Gas through a Quantum Point Contact